Non-volatile memory is becoming standard in consumer appliances such as digital cameras, digital audio players, and personal digital assistants. The demands for affordable non-volatile storage media coupled with the low cost per bit of information achievable in creating write-once storage elements have given rise to the proliferation of write-once memory devices in the consumer marketplace. Write-many file systems are typically not used to store data in write-once memory devices because those file systems are designed to re-write bookkeeping data structures stored in a given set of memory cells whenever data is added or deleted. Instead, specially-designed write-once file systems, such as ISO9660 and Universal Disk Format (UDF), are used. Unfortunately, data stored using a write-once file system typically cannot be read by a write-many file system. This interoperability problem can affect a large number of users since the prevalence of the MS-DOS FAT file system (ANSI/ISO/IEC 9293-1994) in the personal computer space has lead to the broad acceptance of this write-many file system in the nascent consumer appliance market as well.
There is a need, therefore, for a method that can be used to make a write-once memory device read compatible with a write-many file system and, more generally, to make write-once memory devices behave like write-many memory devices.